Apparatus for drying webs



Nov. 28, 1950 B. OFFEN 2,532,032

APPARATUS FOR DRYING WEBS 8 Sheets-Sheet 1 Filed Jan. 28, 1947 INVENTOR.

INVENTOR. fl BY 8 Sheets-Sheet 2 B OFFEN APPARATUS FOR DRYING WEBS Nov.28, 1950 Flled Jan 28 1947 Nov. 28, 1950 B. OFFEN APPARATUS FOR DRYINGWEBS 8 Sheets-Sheet 5 Filed Jan. 28, 1947 IN V EN TOR. fi z/ Nov. 28,1950 a. OFFEN APPARATUS FOR DRYING WEBS 8 Sheets-Sheet 4 Filed Jan. 28,1947 INVENTOR.

Nov. 28, 1950 B. OFFEN 2,532,032

APPARATUS FOR DRYING WEBS Filed Jan. 28, 1947 8 Sheets-Sheet 5 IN VENTOR. mu /4%.

Nov. 28, 1950 B. OFFEN v APPARATUS FOR DRYING WEBS 8 Sheets-Sheet 6Filed Jan. 28, 1947 INVENTOR. fl

Nov. 28, 1950 B. OFFEN APPARATUS FOR DRYING WEBS 8 Sheets$heet 7 FiledJan. 28, 1947 INVENTOR. BY M n 8 W. a m w MW 3 w w S m 2 a m s 8 V. B l-B OFFEN APPARATUS FOR DRYING WEBS Nov. 28, 1950 Flled Jan 28 1947Patented Nov. 28, 1950 UNITED STATES ra'raur *OFFICE APPARATUS FORDRYING WEBS Bernard Ofien, Chicago, Ill. Application January 28, 1947,Serial No. 724,787

17 Qlaims. 1

This invention relates to drying apparatus and more particularly to thedrying of web materials such as paper, textiles, foils and the like.

A difllcult problem involved in the provision of satisfactory dryingequipment is to permit instantaneous stopping of the web in the dryerwhile avoiding damage or injury to the web from radiant heat given oil?by the drying means. Heretofore, it was necessary to bring the press toa slow stop to permit the dryer to cool to prevent burning of the web inthe dryer. Thus, considerable delay was encountered in stopping thepress with consequent waste.

The chief object of the present invention is to provide a dryerincluding a plurality of stages of drying for desired heat applicationto a web which is so arranged as to permit substantially instantaneousstopping of the web in the dryer upon shut-down of the press withoutinjury or damage thereto from radiant heat in the dryer.

An object of the present invention is to provide new and improvedmechanism for automatically moving radiant heating members away from theweb when the press is stopped permitting travel of the web in the dryerto be interrupted without scorching or burning of the web.

A further object is to provide a heating system in which web materialto.be dried is passed through a drying chamber and is contacted byradiant heat and heated air in a plurality of stages if desired; theradiant heating means being moved away from the web and supply of heatedair to the chamber being discontinued upon an interruption in thepassage of the web through the dryer while relatively cold air issupplied to the chamber in contact with the web to prevent scorching orburning which might otherwise occur.

A still further object is to provide a dryer arrangement includingradiant heating means adapted to be moved away from a web in the dryerwhen passage of the web through the dryer is interrupted and in whichshield members are interposed between the web and the radiant heatingmembers when passage of the web through the dryer is interrupted.

A still further object is to provide a method of drying a web such asfreshly printed paper or the like in which the web is effectively driedduring its passage through the dryer while, upon interruption in thepassage of the web through the dryer, burning or scorching of the web isprevented thereby permitting substantially instantaneous stopping of theweb in the dryer and preventing waste created by processes heretoforeknown in which it was essential to decrease the speed of the web slowlyto prevent damage thereto in the dryer. Other objects of my inventionwill be readily perceived from the following description.

This invention relates to apparatus for drying webs comprising incombination, a drying chamber, means for routing a web to be driedthrough the drying chamber, a plurality of burners for directing flamesin the direction of the line of travel of the web, means for moving saidburners toward and from the web, means for supplying heated air over asurface of the web, means for supplying relatively cold air in thechamber whenever travel of a web therein is interrupted, means forsubstantially discontinuing the supply of heated air to the chamberwhenever travel of a web through the chamber is interrupted, and meansfor actuating said burner moving means to move the burners away from theweb whenever travel of a web through the chamber is interrupted wherebysubstantially instantaneous stopping of the web may be effected withoutinjury to the web by radiant heat from the burners.

This invention further relates to a method of drying a web in which thesteps comprise passing a web through a drying chamber, directing radiantheat over the surface of the web in said chamber, directing heated airover a surface of the web in said chamber, then, when travel of the webthrough the chamber is interrupted, moving the radiant heating meansaway from the web, substantially instantaneously discontinuing thesupply of heated air over the web, and directing relatively cold airover the surface of the web thereby permitting substantiallyinstantaneous stopping of the web in the chamber without injury to theweb by radiant heat.

The attached drawings illustrate a preferred embodiment of my invention,in which Figure 1 is a view in front elevation of the dryer illustratingthe means for circulating heated air through the drying chamber;

Figure 2 is a view in side elevation of the equipment shown' in Figure1;

' Figure 3 is a :plan view of the equipment shown in Figure 1;

Figure 4 is a diagrammatic view illustrating the passage of a webthrough the drying chamber and disclosing the damper arrangement andcontrol means therefor;

Figure 5 is a diagrammatic view illustrating the control mechanism forthe damper arrangement:

Figure 6 is a view in front elevation illustrating the mechanism formoving the burners away from the web;

Figure 7 is a view in end elevation of the mechanism shown in Figure 6;

Figure 8 is a view in elevation of the lever actuating mechanism; and

Figure 9 is a diagrammatic view of the control circuit.

Referring to the drawingsfthere is shown a dryer or drying chamber 2containing a plurality of drying stages 3 and 4 through which a web 5 ofmaterial to be dried, as from a letter press or the like, is passed. Web5 paases over a supporting roll 6 through an opening I in dryer 2,through dryer 2 where it is supported by rolls 8 and 3, and leaveschamber 2 through an opening l0, passing over chilling or cooling rollsH. Rolls II are cooled in any suitable manner, preferably by the passageof water therethrough. as is well known in the art, and may be formed ifdesired as disclosed in my copending application. Serial No. 678,519,filed June 21, 1946, now abandoned. Any suitable means, of course, maybe used to forward the web through dryer 2, such means being well knownin the art and preferably being synchronized with the means employed topass the web through the press. Such means may be governed by the presscontroller (refer to Figure 9) to provide for immediate stopping of theweb in the chamber when the press shuts down and to provide immediatestarting of the web in the chamber when the press begins operation.

Within dryer 2, as best shown in Figure 4, are

a plurality of burners 12 adapted to direct flames in the direction ofthe'line of travel of web 5 through the dryer and comprising the firstdrying stage 3. Burners l2 serve as a preheating stage to heat the web 5to a point (below scorching temperature) where the solvents begin toevaporate, drying of the web being completed in a second stage ashereinafter described. Burners I2 extend across dryer 2 and are adaptedto apply radiant heat to web 5. Burners I2 may be of any suitable type,for example, as illustrated in my Patents Nos. 2,421,283 and 2,414,891,granted May 27, 1947 and January 28, 1947, respectively. If desired, thesupply of gas to the burners may be immediately shut off when the web 5for any reason stops and may be adjusted to provide flames of desiredintensity depending on the speed of travel of the web through the dryer.Such burners permit operation with maximum safety despite the use ofdirect flames upon the web for providing intensive drying at high webspeeds.

Suitable mechanism is provided to move burner I2 away from the web topermit substantially instantaneous stopping of the web in the presswithout injury or damage to the web. Such mechanism may include a leverI3 connected to burners l2. Lever i3 is pivoted or swivelled at one endas shown at l4; at its opposite end, lever I3 is pinned as shown at '5to a pneumatic piston ii of well known type. A solenoid valve I1 isplaced in an air line II and is connected to the press controller (referto Figure 9) by wires i9. When the press from which web 5 is suppliedshuts down, wires I! close a circuit to energize solenoid valve II toopen line II to the passage of compressed air. The compressed air passesto piston l5, causing piston ii to raise lever l3 to move burners l2away from the stationary web 5 to the position shown in dotted outline.A second valve 20 is disposed in place the burners l2 in operativeposition adiacent the stationary web.

If desired, a pneumatic piston 23 shown in dotted outline in Figure 4and actuated similarly to piston It may be disposed at the opposite endof the raising mechanism to permit both ends of the mechanism to bemoved away from web 5. While preferred mechanism has been illustratedfor moving burners l2 away from the stationary web 5 it will beunderstood other suitable mechanism may be employed to move the burnersaway from the web when passage of the web through dryer 2 is halted.

A plurality of pipes 24 for the passage of cooling medium such as waterextend across the chamber and are connected to any suitable source ofsupply. Pipes 24 are adapted to be disposed between the web 5 andburners l2 when the burners are moved away from the web. If there is abreak in the web and the web has a tendency to throw itself in anydirection or to weave, then pipe 24 will prevent web 5 from striking theflames of burners l2, and will prevent the web from scorching orburning.

The shield piping 24 (see Figures 6 and 7) is connected to a supplyheader 25 which in turn is connected to an inlet pipe 25. Pip g 24 isalso connected to a discharge header 21 which is connected to an outletpipe 25. Valves 29 and 33 are disposed in pipes 26 and 23 respectivelyto vary the volume of cooling medium such as water or steam directedthrough shield piping 24. In order that piping 24 may be suitablydisposed in dryer 2, adjusting mechanism 3| may be provided to permitpiping 24 to be raised or lowered as required. It will be appreciated,of course, during operation of the dryer, piping 24 is maintained in afixed position. If desired, of course, suitable mechanism, similar tomechanism employed for raising burners l2, may be utilized forautomaticaly moving shield piping 24 downward when the press is stoppedand for raising such piping when the press is again started.

In the second stage 4 of drying, a heated air duct 32 is providedadapted to discharge heated air through a plurality of nozzles 33against one surface of web 5. Nozzles 33 are disposed to dischargeheated air against web 5 after such portion of the web has passedthrough the first stage of drying (burners l2).

A return air duct 34 is connected to the second stage of drying, asillustrated in Figures 1, 2 and 3, and is connected to a fan 35 whichserves to withdraw a major portion of the heated air from the secondstage of drying. Fan 35 is connected by duct 36 to a gas air heater 3'!which in turn, is connected to duct 32 by supply duct 33. A plurality ofgas burners (not shown) are disposed in heater 31 and serve to heat theair passing therethrough. It will be appreciated fan 35 serves to drawair and products of combustion from the second stage 4 of drying,heating the air at heater 3'! and again supplying the heated air throughsupply duct 35 to duct 32 in the second stage of drying, the air beingdistributed through nozzles 33 against one surface of web 5.

When the web is halted in the dryer, fan 35 may be stopped and supply ofgas to the burners of heater 3'! may be discontinued, thereby preventingthe further supply of heated air in the bumers. If desired, fan 35 maybe maintained in service while the heater burners are so operated as tomaintain a desired minimum air temperature available thereby keeping theequipment warm to permit speedy restarting. Likewise, a suitable damperand by-pass arrangement, as shown in my copending application, SerialNo. 523,073, filed February 19, 1944, now Patent No. 2,414,891, may beprovided to permit fan 35 to supply additional cold air to the dryer.

While I have described dryer 2 as including two drying stages in eifecta preheating stage (radiant heat application), and a second stage (hotair application) in which drying is completed, it will be understoodadditional stages may be added if desired. For example, two or morezones or stages of air drying may be provided each with its owntemperature control; in such case, the first stage may comprise webpreheating with a direct flame, the second stage being providedsubstantially as described while a third stage may be provided at alower air temperature permitting final drying without risk of scorching.

At an end of dryer 2, there is a damper arrangement 33 controlled ashereinafter described. An exhaust fan 40 serves to draw a minor portionof air and products of combustion leaking from dryer 2 during normaloperation. Fan 40 is connected to the second drying stage 4 by duct 4!.When damper arrangement 33 is opened, air is exhausted from the dryerinto the room.

Suitable control mechanism for damper ar- To aid in a full understandingof the present invention, the operation of the dryer will be described.It will be understood the dryer is disposed adjacent a letterpress orsimilar equipment rangement 39 is shown in Figure 5. When the press,from which web 5 is fed, is in operation, wires 42 which lead to thepress controller (not shown) will close a circuit to energize solenoid43 to open compressed air inlet valve 44. The compressed air from anysuitable source at a suitable pressure will pass through line 45 todamper operating bellows 46 causing the bellows to expand and, throughlever 41, pivoted at fulcrum 43 and through operating rod 43, effect theclosing of damper 39. When the press stops, it being understood that theweb is at the same time brought to a complete stop in the dryer, thecircuit to the press controller is broken, whereupon solenoid 43 isdeenergized, and the compressed air shut off from bellows 46 whichcontracts. The action of spring 50 assures immediate opening of damper39 to permit air from the room to enter the dryer.

If desired, as shown in Figure 4, high pressure air pipes 5|, connectedto a suitable source of air under pressure, may be disposed adjacent thechilling rolls II and serve to direct streams of air at the web as itpasses over such rolls. Fumes from the dryer 2 follow the web; suchfumes are composed of high boiling point solvents and consequently,there is a tendency to recondense on the chilling rolls and web. Bydirecting streams of high pressure air at the chilling rolls and web asdirected, the fumes or vapors are removed permitting a cleaner sheet tobe obtained.

A cold air duct 52 (refer to Figure 4), is connected to the first dryingstage 3 as shown at 53 and is also connected to a fan or blower 54. Fan54 is connected to the press controller; when the press is about tostop, fan 54 is automatically actuated through the press controller andserves to blow cold air over the web 5 and burners i2 in the first stageof drying to protect the web against scorching when its passage throughthe dryer 2 is halted. Automatically, when the press is again started,fan 54 is cut out by the press controller and discontinues the supply ofcold air to the first stage of drying.

and is employed to dry the web after its passage through the press. Itis desirable that the passage of the web through the dryer becoordinated with the passage of the web through the press. For thispurpose, the actuating mechanism of the dryer may be connected to andactuated by the press controller.

Burners l2 are lit, the flames thereof being directed toward the line oftravel of the web 5 to apply radiant heat to, the web passing throughthe first drying stage 3 of dryer 2, fan 35 and heater 31 are placed inoperation to supply heated air to the second drying stage 4 of the dryerby means of duct 32 and nozzles 33. Exhaust fan 40 is also placedinoperation and serves to remove a minor portion of heated air andproducts of combustion leaking fromdryer 2. Thus, the web 5 being drawnthrough dryer 2 has radiant heat from burners l2 in a first drying stageand heated air from the nozzles 33 in a second drying stage applied toone surface thereof to dry the same. After passage ofweb 5 through dryer2, it is directed over chilling rolls I i to cool the same; chillingrolls II are supplied with cold water to cool the surface of the same asis well known in the art. If desired, high pressure air may be blown onthe rolls H as previously described to remove vapor or fumes from theweb, thereby assuring a cleaner sheet,

Assume, however, that for some reason, passage of web 5 through dryer 2is halted. Immediately, piston I3 is actuated to move burners I2 awayfrom the web. Simultaneously, damper arrangement 39 is opened to permitroom air to enter the dryer and fan 54 is actuated to blow relativelycold air within the first drying stage 3 over the web therein. At thesame time, fan 35 may be stopped and supply of gas to heater 3!discontinued, or supply of gas to heater 31 may be greatly reduced whilefan 35 is continued in operation permitting it to circulate air at amuch lower temperature.

Automatically moving burners l2 away from web 5 in the first dryingstage, automatically discontinuing the supply of air heated to arelatively high temperature to the second drying stage, andautomatically supplying relatively cold airover the web in the firstdrying stage, permits substantially instantaneous stopping of the web 5in dryer 2 without damage or injury to web 5 from the radiant heat ofburners l2. This is an important feature of my invention for it permitsthe press to be brought to what is in effect a dead stop. There is nodelay in stopping the press for it need not be slowed to permit thedryer to cool in order to avoid scorching or burning of the web.Substantially instantaneous stopping; of the press is thus permitted.

Considering Figure 9, the dryer is placed in operation by manuallyclosing switch I04 to start motor 40 actuating exhaust .fan 40 andswitch I05 which closes the circuit to motor IOI actuating thecombustion air blower (not shown) When the contactor is in the oiP'position, relay A is closed, completing the circuit to the motor 54'actuating the cold air fan 54 and solenoid valve il in compressed airline It. The cold air fan 54 is in operation and valve i'l suppliescompressed air to piston ii to move burners l2 away from the stationaryweb. L

When the contactor is in "run position, re-

. B and C close the circuit to the motor 35' of recirculating air fan 35and opens valve to pass air to piston I6 to move the burners to "run"position. Solenoid valve 43 passes air to close dampers I9. Solenoidvalves 31' and I02 in the gas lines are opened to pass gas to theburners i2 and the air heater l1. Solenoid valve I03 is also opened topass water to chilling rolls ll.

Piping 24 for the passage of cooling medium is below the burners l 2when the burners are moved away from the web and is between the web andthe burners when passage of the web through dryer 2 is halted. If thereis a tendency for the web to weave, it will strike the piping and notthe burners which aids in the elimination of any tendency for the web toburn in the dryer. If there is a break in the web causing the paper tothrow itself wildly in any direction, piping 2| prevents the paper fromstriking burners l2 and, since the piping is cool, the paper will notscorch or burn.

The present invention provides a plurality of stages of drying fordesired heat application so arranged as to provide automatic control ofdryer operation, permitting substantially instantae neous stopping ofthe web in the drying chamber and permitting upon start-up of the pressimmediate drying action to occur in the dryer. I have not deemed itnecessary to illustrate specific burner mechanism for the mechanismdescribed and claimed in my copending applications, above referred to,may be employed with satisfactory results.

The mechanism illustrated to move the burners away from the web when theweb is halted is simple and highly effective permitting the burners tobe moved away from the web substantially simultaneously with thestopping of the web since such mechanism is controlled from the presscontroller. The supply of relatively cold air to the first drying stageoccurs substantially simul-'- taneously with the stopping of the web inthe drying chamber for such mechanism is likewise actuated by the presscontroller. In general, the present invention provides simple andeconomical drying equipment arranged in a plurality of stages which maybe employed eifectively to dry a web after its passage through a pressand which is so designated as to prevent scorching or burning of the webin the dryer if for any reason passage of the web through the dryer ishalted. As pointed out above, the web may be halted substantiallyinstantaneously, avoiding the waste heretofore encountered due to thenecessity of slowing down the operation to permit the dryer to cool toavoid damage or injury to the web.

While I have described and illustrated a preferred embodiment of myinvention, it will be understood my invention is not limited theretosince it may be otherwise embodied within the scope of the followingclaims.

I claim:

1. In apparatus for drying webs, the combination of a first dryingstage, a second drying stage, means for routing a web to be driedthrough said drying stages, a plurality of burners in said first dryingstage, for directing flames in the direction of the line oi. travel ofthe web, means for moving said burners toward and from the web, meansfor supplying air heated to a predetermined temperature over a surfaceof the web in the second drying stage, means for circulating relativelycold air in the first drying stage whenever travel of a web through thestages is interrupted, means for discontinuing the supply of air heatedto such temperature to the second drying stage whenever travel of a webthrough the stages is interrupted, and means for actuating said burnermoving means to move the burners away from the web whenever travel 01' aweb through the drying stages is interrupted whereby substantiallyinstantaneous stopping of the web may be effected without injury to theweb by radiant heat from the burners.

2. Apparatus according to claim 1 in which the burners are connected toa lever pivoted at one end, the opposite end of the lever beingconnected to a pneumatic piston, air being supplied to the pistonwhenever travel of a web through the drying stages is interrupted tomove the burners away from the web.

3. Apparatus according to claim 1, in which pneumatic pistons aredisposed at opposite ends of the burner moving mechanism, air beingsupplied to ths pistons whenever travel of a web through the dryingstages is interrupted to move the burners away from the web.

4. Apparatus according to claim 1 in which a plurality of shield membersare interposed between the web and the burners when the burners aremoved away from the web thereby preventing the web from striking theburners and consequent injury thereto upon weaving or breaking of theweb.

5. In apparatus for drying webs, the combination of a drying chamber,means for routing a web to be dried through the drying chamber, aplurality of burners in the chamber disposed as a first drying stage fordirecting flame in the direction of the line of travel of the web, meansfor moving the burners toward and from the web, means for supplyingheated air over a, surface of the web, as a second drying stage. saidchamber having an opening therein for the supply of relatively cold airin the first drying stage, means for automatically circulatingrelatively cold air into the chamber whenever passage of a web throughthe chamber is interupted, means for automatically discontinuing thesupply of heated air in the chamber whenever travel of a web through thechamber is interrupted, and means for automatically actuating saidburner moving means to move the burners away from the web whenevertravel 01' a web through the chamber is interrupted, said automaticmeans cooperating to permit substantially instantaneous stopping of theweb in the chamber without injury to the web by radiant heat from theburners.

6. Apparatus according to claim 5 in which the burners are connected toa lever pivoted at one end, the opposite end of the lever beingconnected to a pneumatic piston, air being supplied to the pistonautomatically whenever travel of a web through the chamber isinterrupted to move the burners away from the web, and a plurality ofmembers having cooling medium passing therethrough are interposedbetween the web and the burners when the burners are moved away from theweb thereby preventing the web from striking the burners and consequentinjury thereto upon weaving and breaking of the web.

7. In apparatus for drying webs, the combination of a drying chamber,means for routing a web to be dried through the drying chamber. aplurality of burners for directing flame in the direction of the line 01travel of the web, means for supplying heated air over a surface of theweb, said chamber having an opening therein for the supply of relativelycold air, a damper arrangement, and means for automaticallydiscontinuing the supply 01' heated air to the chamber,

' opening the damper arrangement, circulating relatively cold air in thechamber, and moving the burners away from the web whenever travel of aweb through the chamber is interrupted thereby permitting substantiallyinstantaneous stopping of the web in the chamber without injury to theweb by radiant heat from the burners.

8. In apparatus for drying webs, the combination of a drying chamber,means for routing a web to be dried through the drying chamber, aplurality of burners for directing flames in the direction oi the lineof travel of the web, a lever connected to said burners, said leverbeing pivoted at one end and connected at its opposite end to apneumatic piston adapted to raise the same, means for actuating thepiston whenever travel of a web through the chamber is interrupted,shield members interposed between the burners and the web when theburners are moved away from the web, means for supplying heated air overheated air over a surface of the web in the chamher, a plurality ofburners for directing flames in the direction of the line of travel ofthe web a surface of the web, said chamber having an v opening thereinfor the supply of relatively cold air, a damper arrangement, means foropening said damper arrangement whenever travel 01 a web through thechamber is interrupted, means for passing relatively cold air throughsaid opening into the chamber whenever travel of a web through thechamber is interrupted, and means tor discontinuing the supply of heatedair to the chamber whenever travel of a web through the chamber isinterrupted, said means cooperating with the burner moving mechanism andthe cold air circulating means to permit substantially instantaneousstopping of the web in the chamber without injury thereto by radiantheat from the burners.

9. In apparatus for drying webs, the combination of a drying chamber,means for routing a web to be dried through the drying chamber, aplurality of burners for directing flame in the direction of the line oftravel of the web, a lever connected to said burners, said lever beingpivoted at one end, a pneumatic piston connected to the opposite end ofsaid lever, means for actuating said piston when travel of the webthrough the chamber is interrupted to move the burners away from theweb, means for supplying heated air over a surface of the web, and meansfor interrupting the supply oi heated air to the chamber and forsupplying relatively cold air to the chamber when travel of the webthrough the chamber is interrupted thereby permitting substantiallyinstantaneous stopping or the web in the chamber without injury to theweb by radiant heat from the burners.

10. Apparatus according to claim 9 in which a plurality of pipes for thepassage of cooling me dium extend across the chamber, said pipes beinginterposed between the burners and the web when the burners are movedaway from the web thereby preventing the web from striking the burnersand consequent injury thereto upon weaving or breaking of the web.

11. In apparatus for drying webs, the combination of a drying chamber,means for routing a web to be dried through the drying chamber, a returnduct connected to the chamber, a fan adapted to withdraw 'air from thechamber, an air heater connected to said fan, a supply duct connectingthe heater and the chamber, said Ian withdrawing air from the chamber,passing withdrawn air through said heater and supplying the in thechamber, means for moving said burners towards and from the web, saidchamber having an opening therein for the supply of relatively cold air,a damper arrangement, means for opening said damper arrangement whenevertravel of a web through the chamber is interrupted, means for supplyingcold air in the chamber whenever travel oil a web through the chamber isinterrupted, means for discontinuing the supply of heated air to thechamber whenever travel of a web through the chamber is interrupted, andmeans for actuating said burner moving means to move the burners awayfrom the web whenever travel of the web through the chamber isinterrupted whereby substantially instantaneous stopping of the web maybe effected without injury to the web by radiant heat from the burners.

12. In apparatus for drying webs, the combination of a drying chamberarranged in a plurality of stages, means for routing a web to be driedthrough the drying chamber, said chamber having an opening therein for,the supply of cold air to the chamber, an exhaust fan adapted to exhausta minor portion-oi heated air leaking from the chamber, a plurality ofburners disposed in a first drying stage in said chamber for directingflames in the direction oi the line of travel of the web in the chamber,means for moving said burners toward and from the web, a fan connectedto the chamber by a return duct, a gas air heater connected to the fan,a supply duct connecting the heater and the fan to the chamber to permitthe fan to supply air heated to a predetermined temperature to a seconddrying stage in the chamber, a damper arrangement, means forautomatically opening the damper arrangement whenever travel of a webthrough the chamher is interrupted, means for automaticallydiscontinuing the supply of air heated to such temperature to the seconddrying stage whenever travel of a web through the chamber isinterrupted, means for automatically actuating said burner moving meansto move the burners away from the web whenever travel of the web throughthe first drying stage is interrupted, a fan for automatically blowingcold air in the first drying stage whenever travel of a web therethroughis interrupted, and a plurality of pipes for the passage of coolingmedium extending across the chamber, said pipes being interposed betweenburners and the web when the burners are moved away from the web, saidautomatic means cooperating to permit substantially instantaneousstopping of the web in the chamber without injury to the web by radiantheat from the burners.

13. Apparatus according to claim 12 in which the means for moving theburners toward and from the web comprise a lever connected to theburners, said lever being pivoted at one end, a pneumatic pistonconnected to the opposite end of the lever, and means for automaticallysupplying air to the piston to raise the lever carrying the burnerstherewith when passage of a web through the chamber is interrupted.

14. In a method of drying a web, the steps which comprise directingradiant heat over the surface of a web in a first drying stage,directing air heated to a predetermined temperature over a surface ofthe web in a second drying stage, then, when travel of the web throughthe stages is 11 interrupted, substantially instantaneouslydiscontinuing the supply of air heated to such temperature over the web,moving the radiant heating means away from the web, and directingrelatively cold air over the surface of the web in the tint drying stagethereby permitting substantially instantaneous stopping of the web inthe chamber without injury to the web by radiant heat.

15. In a method of drying a web, the steps which comprise passing a webthrough a chamber, directing radiant heat over the surface of the web insaid chamber, directing heated air over a surface of the web in saidchamber, then, when travel of the web through the chamber is interruptediscontinuing the supply of heated air over the web, moving the radiantheating means away from the web, placing shield members between theradiant heating means and the web when such members are moved away fromthe web, and directing relatively cold air over the surface of the webin said chamber thereby permitting substantially instantaneous stoppingof the web in the chamber without injury to the web by radiant heat.

16. In a method of drying a web, the steps which comprise passing a webthrough a chamber, directing radiant heat over the surface of the web insaid chamber, directing heated air over a surface of the web in saidchamber, then, when travel of the web through the chamber isinterrupted, substantially instantaneously discontinuing the supply ofheated air over the web, moving the radiant heating means away from theweb, and directing relatively cold air over the surface of the webthereby permitting substantially instantaneous stopping of the web inthe 12 fihaznber without injury to the web by radiant 17. In a method ofdrying a web, the steps which comprise passing a web through a dryingchamber, directing radiant heat over the surface of the web in a firstdrying stage in said chamber, directing heated air over a surface of theweb in a second drying stage in said chamber, then, when travel of theweb through the chamber is interrupted, automatically moving the radiantheating means away from the web, automatically interrupting the supplyof heated air over the web, automatically opening a damper arrangementto permit room air to enter the drying chamber, and automaticallysupplyin relatively cold air over the surface of the web in the firstdrying stage, thereby permitting substantially instantaneous stopping ofthe web in the chamber without injury to the web by radiant heat.

BERNARD OFFEN.

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